Novel modulation concept of the SWISS rectifier preventing input current distortions at sector boundaries

This paper describes a new modulation concept for the uni- and bidirectional SWISS rectifier which mitigates input current distortions at the gird voltage sector boundaries. An analytical model is derived and compared to simulations, showing that these distortions are increasing the input current THD significantly. Furthermore, an algorithm is presented which allows the calculation of a temporary pulse width modulation for the SWISS Rectifier´s active 3^rd harmonic current injection network which mitigates the distortions. Simulations show that the AC input currents´ THD can be reduced from 4.2 % to 0.8 % on a prototype system. The concept is verified by measurement results taken on a bidirectional 7.5 kW SWISS Rectifier prototype.